Like a victim caught in the middle of heavy gun fire, Earth lies in the center of a deadly cosmic hail storm. Yet we know little about the countless objects hurdling around us. Cataclysmic events on one of our planetary neighbor gave us a sobering reminder that we could be next. It's not a case of if, but rather when Earth will be hit by an asteroid or comet. Humanity might have the means to fight back but only if we have fair warning of the Cosmic Collision.